1. Field of the Invention
This invention relates to a chlorine-containing resin molding, and more particularly to a chlorine-containing resin molding which contains no stabilizer consisting of metallic salts such as plumbum (Pb) or tin (Sn). Further consideration is given to the application of nonmetallic coloring agents and lubricants to the molding. This invention relates further to molding material (composition of matter) for obtaining the molding.
2. Prior Art
Polyvinyl chloride (hereinafter referred to as PVC) representative of chlorine-containing resin is widely used in the form of synthetic resin molding because it is inexpensive, strong and excellent in chemical resistance and secondary processing property. The PVC resin, because of its structural properties, is deprived of hydrochloric acid with H and Cl element freed of PVC by temperatures in time of molding and polyene is formed in the PVC resin, and when the polyene continues to be more than seven atoms, it develops into chromophore and the PVC resin turns light yellow by the chromophore. If the polyene chain of this chromophore is increased in length, the PVC resin turns gradually yellowish brown until finally the brown changes into black. Accordingly, stabilization of PVC resin means, in short, prevention of this change in color, and in other words, it means prevention of production of polyene, namely, suppression of freeing of hydrochloric acid from the PVC resin. From this viewpoint, it is general practice to add a PVC resin stabilizer beforehand to the PVC resin material. It is generally know that stabilizers of metallic compounds including a metallic element such as Pb or Sn are chiefly used as a stabilizer of the type described, and it is also true that the stabilizers are used in chlorine-containing resins other than the PVC resin.
Also, it is general practice to add a so-called lubricant such as higher fatty acid represented by stearic acid to the chlorine-containing resin in order to improve the releasing property of the resin in time of molding and also to improve appearance (especially, luster, gloss or the like) of finished moldings.
As well known, remarkable progress has recently been made in the development of electronic parts with semiconductors as a main item, and synthetic resin moldings have come to be widely used in the equipment for manufacturing the electronic parts, in the packaging containers for the parts, in the housings of the machines and appliances in which the electronic parts are used, and in other related machines and appliances. Such manufacturing equipment requires various kinds of processing in the step of manufacture, and packaging containers, machine and appliance housings require such processing as picking or washing. Accordingly, the PVC resin molding which contains a metallic compound such as Pb or Sn as a stabilizer metallic element ion is dissolved from the resin molding during the processing and produced adverse effects on the electronic parts or like articles manufactured, with the result that it was impossible to use the PVC resin molding as one for use with high-quality semiconductors such as a 1-megabit semiconductor.
Besides, it was a cause of various troubles that metallic ion dissolves from the PVC resin molding which has been widely used in the industrial field related with biochemistry, medical treatment, pharmaceuticals, foodstuff, etc.
Epoxy compounds, organic phosphorous ester, phenol derivatives, polyhydric alcohol, etc. are known as PVC resin stabilizers other than metallic salts, but even if they were used in single, they were not yet sufficient for thermal stabilization, so that they had to be used in combination with the aforestated metallic salts. From the circumstances above, fluororesin excellent in thermal stability as a synthetic resin suitable for the above-mentioned purposes is used by some users, but the fluororesin suffers from the disadvantages that it is expensive and is difficult of being subjected to secondary processing such as welding. Because of the disadvantage, the fluororesin lacks wide applicability. Accordingly, there was strong desire for application of chlorine-containing resin free of such a disadvantage to the uses described above.
The aforementioned lubricant was effective for improving moldability but had the disadvantage it reduced thermal deformation temperature (heat softening temperature, heat distortion temperature) and accordingly, measures were also necessary in this respect for making the lubricant suitable for a high temperature use out of the above uses.
Furthermore, in the uses of synthetic resin moldings related with semiconductor items, there are some cases wherein the resin moldings must be opaque or translucent (hereinafter referred to as non-light-transmittability) depending upon the purpose of use. In such a case, a metallic coloring agent such as titanium oxide is beforehand mixed into a resin material and molded. But in the various steps of processing, a metallic element ion dissolves from the moldings colored with a metallic coloring agent and often provided a cause of similar troubles and could not fully meet requirements for colored moldings.